Thiomethylals and preparation thereof



United States Patent r 3,006,965 THIOMETHYLALS AND PREPARATION THEREOFGerhard Schrader, Wuppertal-Cronenberg, Germany, as-

signor to Farbenfabriken Bayer Aktiengesellschaft,

Leverkusen, Germany, a corporation of Germany No Drawing. Filed Feb. 12,1958, Ser. No. 714,696 Claims priority, application Germany Mar. 1, 19575 Claims. (Cl. 260-609) The present invention relates to and has as itsobjects new and useful thiomethylals of the following general formulawherein R stands for a cycloalkyl radical or for an alkyl radical havingl-lZ carbon atoms which may be substituted, or for the cyano radical,are excellent insecticides. More specifically R stands for cyclo alkylradicals containing 5 to 6 carbon atoms. The alkyl radical ifsubstituted, preferably bears 1 or 2 substituents of mercaptans. v

This reaction may be seen from the following formula In this formula Rhas {the same significance as shown above.

. The preparations obtainable according to this process are chieflywater-insoluble oils, some of which may be distilled withoutdecomposition under a high vacuum. Partly, solid compounds are obtainedwhich may be recrystallized from suitable organic solvents.

The new compounds are distinguished by an insecticidal activity. It is acharacteristic feature of most of the compounds of this class to have adistinct acaricidal action. The compounds according to the invention areemployed in a manner commonly used for plant-protecting agents, i.e.they are preferably used in combination with liquid or solid diluents orfillers. Fillers and diluents of this kind are for example talcum,chalk, benton- "ite, and alumina, on the one hand, or, in the case ofliquid agents, preferably Water (if desired in combination with acommercial emulsifier, such as preferably aromatic polyglycolethers eg.a commercially available benzylhydroxy diphenyl polyglycolethercontaining about gly-.

. col residues) as well as low molecular weight alcohols,

Killing rate has been determined after 24 hours.

hydrocarbons and the like. A preferred method of application consists inusing a dusting or spraying process. As an example for the specialutility of the inventive compounds the compounds of the followingformulae 01- S CHz-S C N Cl S-CHr-SCmHrs (III) CH3 01 S C Hr- S -CH havebeen tested against spider mites (tetranychus althaeae Hanst) andcaterpillars (larvae of diamond black moth). Tests have been carried outas follows: plants (nasturtium plants in case of spider mites and whitecabbage in case of caterpillars) have been sprayed drip wet. Thefollowing results have been obtained:

(1) Spider mites, 0.1%, 100% (II) 'Spider mites, 0.1%, 100% 2 (III)Caterpillars, 0.1%, 100%.

The solutions of the active ingredients have been prepared as follows:equal amounts of active ingredient and dimethyl formamide have beenmixed, whereafter 20% by weight referred to active ingredient of acommercially available emulsifier (such as benzylhydroxy diphenylpolyglycolether containing about 15 glycol residues) are added. Thispremixture then is diluted with water to a concentration of 0.1%.

The following examples are given by way of illustration only without,however, limiting the present invention thereto:

Example 1 21 grams of sodium thiocyanate are dissolved in millilitres ofmethanol. 59 grams of u-chloromethyl-(4- chlorophenyl)-thioether areadded at 50 C. with stirring Whilst maintaining the temperature at 50 C.for 2 hours. The mixture is then cooled to room temperature, the sodiumchloride formed is filtered off by suction and the solvent removed byvacuum distillation. After standing for a brief period, the residuesolidifies. Upon recrystallisation frorn ligroin, 45 grams of a-methylthiocyanate-(4-chlorophenyl) thiomethylal of MP. 69 C. is obtained.

Administered to the rat per os 1000 mg./kg. do not show any symptoms.0.0001 percent solutions kill mosquito larvae 0.1 percent solutions killred spider mites and black bean aphids completely.

Example 2 oil is taken up in benzene, the benzenic solution is 3 washedwith water and dried over sodium sulfate. After removal of the solventby vacuum distillation 83 grams of p-chlorophenyl-dodecylthiomethylal ofB.P. 167 -C./0.01 mm. Hg are thus obtained.

Administered orally to the rat, 1000 mg./kg. do not show' any symptoms.0. 1 percent solutions kill mosquito larvae, aphids and spider mitescompletely. Caterpillars are also killed completely with. 0.1 percentsolutions.

Example 3 37 grams of 3.4-dichlorophenyl mercaptan are dissolved in 63grams of a sodium eth-ylate solution (cone-- Example 4 Cl-Q-S-CHaS-CH 31grams of a-chloromethyl-isopropyl-thioether (B.P. 145 C./ 15 mm. Hg) areadded dropwise with stirring to a mixture of 39 grams of p-chlorophenylmercaptan and 78 grams of a sodium ethylate solution (corresponding to Aof sodium ethylate) and 100 millilitres of anhydrous alcohol. Thetemperature rises spontaneously to 60 C. and is maintained for one hour.After working up in usual manner 49 grams (corresponding to 85 percentof the theoretical) of p-chlorophenyl-isopropyl-thiomethylal of B.P. 95C./0.01 mm. Hg are thus obtained.

Toxicity on the rat orally: LD 1000 mg/kg. 0.1 percent solutions killcaterpillans 100%. In a similar manner the following compounds may beobtained:

CH1 Cl S-CHr-S-CH Cam B.P. 115 C./0.01 mm. Hg;

CaHa

B.P. 100 C./0.01 mm. Hg;

ClQ-S-CHz-S-OlEh-OHr-Cl cockroaches are killed completely with solutionof 0.1 percent; B.P. 110 C./0.01 mm. Hg;

0.1 percent solutions kill black bean aphids 50%; B.P.

with 0.1% solutions black bean aphids are killed 60%;

with 0.1 percent solution-s spider mites are killed 50%;

MP. 62 C.;

black bean aphids are killed completely with solutions of 0.1%, 0.1%solutions show a strong ovicidal activity against the eggs of redspiders; B.P. C./0.01 mm.

GIG-S-CHPSGMHK with solution of 0.1% caterpillars are killed 50%; B.P.C./0.0I mm. Hg.

I claim:

1. The compound of the following formula 2. The. compound of thefollowing formula 3. The compound of the following formula 4. Thecompound of the following formula 5. A thiomethylal of the generalformula X I R-S-CHz-SQ-Ol wherein R stands for a member selected fromthe group consisting of cycloalkyl radicals containing 5 to 6 carbonatoms, chloro-substituted lower alkyl radicals and chlorosubstitutedphenylmercaptomethyl radicals; and X stands for a member selected fromthe group consisting of hydrogen and chlorine.

References Cited in the file of this patent UNITED STATES PATENTS2,490,875 Landau Dec. 13, 1949 2,617,818 Mowry Nov. 11, 1952 2,645,592Campbell July 14, 1953 2,665,202 Mowry Jan. 5, 1954 2,743,210 Jones Apr.24, 1956 2,788,355 Bullock Apr. 9, 1957 2,789,990 Bullock Apr. 23, 19572,797,246 Barber June 25, 1957 2,801,261 Hornberger July 30, 19572,802,769 Van Stryk Aug. 13, 1957

5. A THIOMETHYLAL OF THE GENERAL FORMULA